Prokaryotic and eukaryotic cells are often used as efficient expression systems for the production of recombinant proteins. To obtain proteins which are of satisfactory purity and quality affinity chromatography methods are very often employed. An example of such chromatography is immobilized metal affinity chromatography (IMAC). To use this technology a short histidine tag (His-tag), composed usually of six successive repetitions of histidine residue must, be fused with the target protein. The His-tag can reversibly bind to certain metal ions (e.g. cobalt, copper, nickel and zinc). Using an appropriate carrier containing one of these ions the purification or immobilisation of His-tag proteins is possible. A His-tag attached to recombinant proteins can be used to detect them by the western blotting technique, using mono- or polyclonal antibodies directed against the tag. This protein detection system can be used in other in vitro techniques which are used to study interactions between proteins, such as pull down, co-immunoprecipitation or Far Western blotting.
DNA aptamers are defined as single-stranded deoxrybonucleic acid molecules of about 40-100 nucleotides in length, which have the ability to bind a ligand with high specificity and affinity. The rich secondary and tertiary structures of the aptamer mean that the matching of a selected aptamer with a target molecule is optimal.
The objective of this invention is to provide a new method for the identification of molecules containing a histidine tag, in particular through the provision of new molecules with a strong affinity for a molecular target containing a histidine tag, or any molecule (e.g., peptide, protein, DNA derivative) containing a histidine hexamer.
The technical aim specified above may be implemented in accordance with the discussed invention.